One thing I do when attaching the solid plastic eyes that Capt. Lemay uses is after I clip the stem off, I lightly sand the back of the eye by moving it back and forth on an emery board. It seems to bond better that way, at least for me.
I have found that if I use the domed eyes, I use alcohol to remove the adhesive from the eye prior to glueing it on the fly. I have had flys that after they were used a while, I would only have the silver backing left on the fly.
The eyes mentioned by Bob Lemay are the ones I use the most now.